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  1. #31
    Moderator abu baniaz's Avatar

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    Using a Sundtek, these were the details on 482 MHz. It was mainly on 100 but had the odd fluctuation that I seem to have caught

    <e2frontendstatus>
    <e2snrdb>96 dB</e2snrdb>
    <e2snr>96 %</e2snr>
    <e2ber>0</e2ber>
    <e2acg>96 %</e2acg>
    </e2frontendstatus>

    With the PNP tuner these were the details on the same frequency

    <e2frontendstatus>
    <e2snrdb>100 dB</e2snrdb>
    <e2snr>100 %</e2snr>
    <e2ber>0</e2ber>
    <e2acg>95 %</e2acg>
    </e2frontendstatus>


    Other various screenshots with names to explain what they are.
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  2. #32
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    @au baniaz:

    The Sundtek figures show the same sort of problems as seen by ccs - most obviously the 96 dB SNR is too large to be plausible, and the associated % figure should be 100% if that were correct.

    Perhaps of greater concern to me is that the PNP tuner looks as if it has similar problems, which might indicate that part of the problem lies in OpenVix rather than the drivers. Alternatively perhaps the two devices use the same chipsets and similar drivers.

    EMJB
    Xtrend Xt10000 with 3 Freeview tuners

  3. #33
    Moderator abu baniaz's Avatar

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    Quote Originally Posted by EMJB View Post
    which might indicate that part of the problem lies in OpenVix rather than the drivers.
    I have tried OpenPLI and Pure E2. They are the same. Which image does not have this issue/problem? Please suggest it.

  4. #34
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    @abu baniaz:

    Again you are reading something into my words that I did not intend. When I said that part of the problem might be in OpenVix rather than the drivers, I meant just that, not that it didn't exist in other images.

    A possible source of any problems that might exist in OpenVix is frontend.cpp. Please excuse my ignorance of the details of the relationships between images, but I understand that until fairly recently a common version of this file was used across several (or all) images, so it would not be surprising if similar problems exist in many images' versions of frontend.cpp (if they exist at all).

    The ideal way forward would seem to me to be to generate a new version of the enigma file with additional logging in frontend.cpp. However the versions birdman helped me create were ~26 MByte, making it difficult to ask ccs to test these for us as email is the only way I have of sending him such files.

    The only other experiment I can think of would be for you to try selecting the legacy stats for the affected tuners - if the results are the same it might be the result of lack of driver support for the new DVB API, requiring special fudge factors in frontend.cpp as is already provided for the "Sundtek DVB-T (III)" tuner.

    EMJB
    Xtrend Xt10000 with 3 Freeview tuners

  5. #35
    Moderator abu baniaz's Avatar

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    You can upload a modified cpp file. I'll ask Huevos to build with it if he has time as I usually run images from his fork as my build machine is snookered at the moment.

  6. #36
    ViX Beta Tester birdman's Avatar

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    Quote Originally Posted by EMJB View Post
    The ideal way forward would seem to me to be to generate a new version of the enigma file with additional logging in frontend.cpp. However the versions birdman helped me create were ~26 MByte, making it difficult to ask ccs to test these for us as email is the only way I have of sending him such files.
    They become much smaller if you strip them.
    Doesn't seem to be packaged for Vix, but there must be one around somewhere (I suspect the one from a Debian mips system would work...)

    EDIT (fyi):
    It turns out that a strip is built that runs on the native architecture of the build, but works on binaries of the architecture of the box build-for.

    So, for my et8000 I get this Intel-x64 binary:

    oe-alliance/builds/openvix/developer/et8000/tmp/work/et8000-oe-linux/linux-etxx00/linux-etxx00-4.10.6-.4/recipe-sysroot-native/usr/bin/mipsel-oe-linux/mipsel-oe-linux-strip


    which strips mips binaries when run on Ubuntu.
    Last edited by birdman; 08-02-19 at 02:17.
    MiracleBox Prem Twin HD - 2@DVB-T2 + Xtrend et8000 - 5(incl. 2 different USBs)@DVB-T2[terrestrial - UK Freeview HD, Sandy Heath] - LAN/USB-stick/HDD

  7. #37
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    Quote Originally Posted by abu baniaz View Post
    You can upload a modified cpp file. I'll ask Huevos to build with it if he has time as I usually run images from his fork as my build machine is snookered at the moment.

    Thanks - will do a build for my machine with the new file and check the logging before I upload it, so it will probably be 2-3 days, perhaps more.

    EMJB
    Xtrend Xt10000 with 3 Freeview tuners

  8. #38
    Moderator abu baniaz's Avatar

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    If it works, just submit a pull request.

  9. #39
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    Quote Originally Posted by abu baniaz View Post
    If it works, just submit a pull request.
    What I will propose will almost certainly produce too much log information to be permanently incorporated. I am expecting to log 5 or 6 items per call for either the dB or the % figure, but each occur several times a second while running Signal Finder so one could easily end up with 1000s of lines in the log.

    EMJB
    Xtrend Xt10000 with 3 Freeview tuners

  10. #40
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    @abu baniaz:

    Version of frontend.cpp with the additional logging attached with a ".txt" suffix to allow me to upload it - as I said in my previous post this will generate large amounts of log data so I would recommend that you do not use it for any other investigations etc. If you could collect a log including each of your DVB-T tuners on just one typical frequency that should help. Note that one second on each tuner will collect more than enough information.

    In producing this, it has come to my attention that what Frequency Finder & OpenWebIf call "AGC" is called "Signal strength" or similar in the API, and in the case of the new API is a number of dBs which is normally negative, not a percentage.

    EMJB
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    Xtrend Xt10000 with 3 Freeview tuners

  11. #41
    Moderator abu baniaz's Avatar

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    Logs attached. I went into signal finder and went between the frequencies.
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  12. #42
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    Quote Originally Posted by EMJB View Post
    . and in the case of the new API is a number of dBs which is normally negative, not a percentage.
    Now not sure that this part is correct - in spite of the name give by frontend.cpp I think the signal strength may be a percentage of a maximum, which would explain its similarity to the snr% figure. I need to trace all the signals through from API to users to follow the changing names to be sure of what is going on.

    EMJB
    Xtrend Xt10000 with 3 Freeview tuners

  13. #43
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    Quote Originally Posted by abu baniaz View Post
    Logs attached. I went into signal finder and went between the frequencies.
    Thanks - will try to look at them tomorrow.

    EMJB
    Xtrend Xt10000 with 3 Freeview tuners

  14. #44
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    I've had a look at the logs. The major issue seems to be the following sequence:

    1. FrontendStatus.py line 25 equates the "AGC"% value to "tuner_signal_power"
    2. python_helpers.cpp equates this to eDVBFrontendStatus::getSignalPower()
    3. frontendparms.cpp line 84 equates this to frontend.cpp's "iFrontendInformation_ENUMS::signalPower",
    4. frontend.cpp equates this to the new API relative signal strength, not the absolute signal strength in dBm (see https://linuxtv.org/downloads/v4l-dv...ignal-strength)


    as indicated in my penultimate post.

    Unfortunately the new API is rather vague about how the relative signal strength is to be calculated, and I would not be surprised if drivers just equate this to the relative SNR.

    In terms of specific issues arising rom the Sundtek log, I noticed that while the new API returned a value for relative (i.e. %) SNR it did not do so for the absolute (dB) value. While frontend.cpp calculates a missing relative value from the absolute value, the reverse is not true, forcing the use of the legacy API. In the absence of tuner-specific code this can produce silly answers.

    The PNP log shows that frontend.cpp thinks that this tuner supports the new API, but never gets any data from it, and so always reverts to the legacy API. Aagin, in the absence of tuner-specific code this can produce silly answers.


    EMJB
    Xtrend Xt10000 with 3 Freeview tuners

  15. #45
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    On my Unicable LNB, AGC is 80% on every channel I've tried, and SNR 69% to 80% depending on channel (not tried them all, but every one I've tried AGC is 80)

    On my other normal LNB motorised dish, AGC varies from 72 to 82% depending on the channel

    unicable.PNGnot unicable.PNG

    This is on my Gigablue UHD UE 4K

  16. The Following User Says Thank You to Ojustaboo For This Useful Post:

    EMJB (10-03-19)

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